Le Chatelier's Principle: Equilibrium Shift with Pressure Change

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Discussion Overview

The discussion revolves around Le Chatelier's Principle and its application to equilibrium shifts in response to changes in pressure. Participants explore the implications of pressure changes on chemical equilibria, particularly in the context of gaseous reactions.

Discussion Character

  • Homework-related
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant asserts that increasing pressure will shift the equilibrium to the side with fewer moles of gas, suggesting a shift to the left in their specific case.
  • Another participant points out that the principle applies specifically to gases and questions the state of all present substances in the equilibrium.
  • A third participant expresses dissatisfaction with the terminology used to describe equilibrium shifts, advocating for a focus on constants such as the equilibrium constant and concentration of water instead of the directional shifts.
  • This participant also prompts consideration of how changes in pressure affect other variables in the equilibrium equation.

Areas of Agreement / Disagreement

Participants exhibit disagreement regarding the interpretation of equilibrium shifts and the terminology used. There is no consensus on the best way to conceptualize these shifts or the implications of pressure changes on the equilibrium.

Contextual Notes

Some assumptions about the states of substances involved in the equilibrium are not clarified, which may affect the interpretation of the pressure change's impact. The discussion does not resolve the mathematical or conceptual nuances surrounding the application of Le Chatelier's Principle.

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Homework Statement


upload_2019-1-4_11-3-10.png


Homework Equations


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The Attempt at a Solution


I know that the equilibrium will shift to the side with fewer moles of molecules when the pressure is increased according to le Chatelier's principle, so I thought in this case it would shift to the left as there is only 1 mole of gaseous atom compared to 2 moles on the right-hand side. The answer is A, however. Thanks in advance!
 

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H+(aq) and HCO3-(aq) are ions in the aqueous solution.
 
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youmei0426 said:
I know that the equilibrium will shift to the side with fewer moles of molecules when the pressure is increased

As worded it is true for gases only, not in general.

As @Lord Jestocost already hinted, check state of all present substances. How many are gases?
 
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Time to say after half a century I have always hated from the very beginning this expression "The equilibrium shifts to the left (or the right)." I at first indeed did not know what that meant, well I picked it up from the way the teacher repeatedly used it, but I do not think it is good wording. That said, you will meet it.

The way I think is, there is something that is constant, the equilibrium constant.
In this example there is another thing that you can take as constant, the concentration of water.
That being so, and looking at your equation and looking also the corresponding equation that defines the equilibrium constant, when the pressure of CO2 increases, what else must change and how?

I think that is a better way of thinking than being bamboozled by words.
 
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